The invention relates to a device for doubling the frequency of a light wave, in which device a fundamental light wave is guided through a nonlinear optical medium while forming a second harmonic wave.
The invention also relates to potassium-rubidium-lithium niobate crystals and to a method of manufacturing such crystals.
The device according to the invention may be used, for example, in combination with a semiconductor laser light source which generates red light, as a compact blue light source for optical storage of information, for telecommunication and for laser printers. By virtue of the use of shortwave light, the information density can be increased and the possibilities of writing and erasing information are extended as a result of the greater photon energy.
In European Patent Application EP 90201923.1, a device for doubling the frequency of a light wave is described, a fundamental light wave being generated by a semiconductor laser light source and guided through a nonlinear optical medium while forming a second harmonic wave, said nonlinear optical medium being formed from a stoichiometric potassium-lithium niobate crystal. In such a device, frequency doubling at room temperature is optimal at a wavelength of the fundamental light wave of 803 nm. In experiments leading to the invention, it was established that, using the known device, the shortest wavelength which can be attained by frequency doubling is approximately 396 nm.